About this tool
The Brewing Water Salt Addition Calculator shows how common brewing salts change your water's mineral profile, so you can steer a source water toward a target ion balance for a given beer style. Start with your source water's ion concentrations in ppm (mg/L) — calcium, magnesium, sulfate, chloride, sodium, and bicarbonate — enter the batch volume and the grams of each salt you plan to add, and the tool reports the resulting profile plus the all-important sulfate-to-chloride ratio. All chemistry runs locally in your browser.
Each salt adds ions in fixed proportions set by its formula weight. Per gram dissolved in one litre: gypsum (CaSO₄·2H₂O) adds 232.7 ppm Ca and 557.9 ppm SO₄; calcium chloride (CaCl₂·2H₂O) adds 272.6 ppm Ca and 482.3 ppm Cl; epsom salt (MgSO₄·7H₂O) adds 98.6 ppm Mg and 389.7 ppm SO₄; baking soda (NaHCO₃) adds 273.7 ppm Na and 726.4 ppm HCO₃. The concentration increase is (grams × factor) ÷ litres, added to the source level. Volume entered in gallons is converted with 1 gal = 3.78541 L before the division.
The sulfate-to-chloride ratio guides flavour balance: a ratio well above 1 (sulfate-forward, e.g. 2:1 or higher) accentuates hop bitterness and dryness for pale ales and IPAs, while a ratio below 1 (chloride-forward) rounds out malt for stouts, bitters, and lagers; near 1:1 is balanced. As an example, adding 2 g gypsum and 1 g calcium chloride to 20 L raises calcium by about 37 ppm, sulfate by about 56 ppm, and chloride by about 24 ppm, for a sulfate-to-chloride ratio near 2.3. Keep calcium roughly 50–150 ppm and adjust salts to hit your target ratio.